It has generally been known that cardiac stimulation can be carried out by means of external electrodes positioned against the chest and back of a patient. One such system has been disclosed in U.S. Pat. No. 4,349,030 to Belgard et al. entitled "External Noninvasive Electric Cardiac Stimulation."
It has also been generally known, as an alternate to the use of exterior electrodes placed on the body of a patient, to position swallowable electrodes in the esophagus at the level of the atria. Such esophageal electrodes have been disclosed in various articles such as "A Pill Electrode For The Study of Cardiac Arrhythmia", R. Arzbaecher, Medical Instrumentation Vol. 12 - No. 5, 1978; and "Use of the Pill Electrode for Transesophageal Atrial Pacing", Jenkins et al., PACE Vol. 8, July-August 1985.
Notwithstanding their utility and success, the prior art esophageal electrodes have been formed from separate components mechanically assembled together into a completed electrode. There continues to be a need for an electrode with all components inseparatably bonded together in such a form that the device can be inserted and removed with little or no abrasion or trauma to the esophagus of the patient.
A disadvantage of the known electrodes is that the tolerance of the extruded TEFLON.RTM. tubing used therein can not be adequately controlled. As a result, there is an inordinate amount of wasted tubing. This also translates into labor wasted in unsuccessful attempts to assemble the device.